NetworkManager/src/core/settings/nm-secret-agent.c

/* SPDX-License-Identifier: GPL-2.0-or-later */
/*
 * Copyright (C) 2010 - 2011 Red Hat, Inc.
 */

#include "src/core/nm-default-daemon.h"

#include "nm-secret-agent.h"

#include <sys/types.h>
#include <pwd.h>

#include "libnm-glib-aux/nm-c-list.h"
#include "libnm-glib-aux/nm-dbus-aux.h"
#include "nm-dbus-interface.h"
#include "libnm-core-intern/nm-core-internal.h"
#include "libnm-core-aux-intern/nm-auth-subject.h"
#include "nm-simple-connection.h"
#include "NetworkManagerUtils.h"
#include "c-list/src/c-list.h"

/*****************************************************************************/

#define METHOD_GET_SECRETS        "GetSecrets"
#define METHOD_CANCEL_GET_SECRETS "CancelGetSecrets"
#define METHOD_SAVE_SECRETS       "SaveSecrets"
#define METHOD_DELETE_SECRETS     "DeleteSecrets"

enum {
    DISCONNECTED,

    LAST_SIGNAL
};

static guint signals[LAST_SIGNAL] = {0};

typedef struct _NMSecretAgentPrivate {
    CList                     permissions;
    CList                     requests;
    GDBusConnection          *dbus_connection;
    char                     *description;
    NMAuthSubject            *subject;
    char                     *identifier;
    char                     *owner_username;
    char                     *dbus_owner;
    GCancellable             *name_owner_cancellable;
    guint                     name_owner_changed_id;
    NMSecretAgentCapabilities capabilities;
    bool                      shutdown_wait_obj_registered : 1;
} NMSecretAgentPrivate;

struct _NMSecretAgentClass {
    GObjectClass parent;
};

G_DEFINE_TYPE(NMSecretAgent, nm_secret_agent, G_TYPE_OBJECT)

#define NM_SECRET_AGENT_GET_PRIVATE(self) \
    _NM_GET_PRIVATE_PTR(self, NMSecretAgent, NM_IS_SECRET_AGENT)

/*****************************************************************************/

#define _NMLOG_PREFIX_NAME "secret-agent"
#define _NMLOG_DOMAIN      LOGD_AGENTS
#define _NMLOG(level, ...)                                                       \
    G_STMT_START                                                                 \
    {                                                                            \
        if (nm_logging_enabled((level), (_NMLOG_DOMAIN))) {                      \
            char _prefix[64];                                                    \
                                                                                 \
            if ((self)) {                                                        \
                g_snprintf(_prefix,                                              \
                           sizeof(_prefix),                                      \
                           _NMLOG_PREFIX_NAME "[" NM_HASH_OBFUSCATE_PTR_FMT "]", \
                           NM_HASH_OBFUSCATE_PTR(self));                         \
            } else                                                               \
                g_strlcpy(_prefix, _NMLOG_PREFIX_NAME, sizeof(_prefix));         \
                                                                                 \
            _nm_log((level),                                                     \
                    (_NMLOG_DOMAIN),                                             \
                    0,                                                           \
                    NULL,                                                        \
                    NULL,                                                        \
                    "%s: " _NM_UTILS_MACRO_FIRST(__VA_ARGS__),                   \
                    _prefix _NM_UTILS_MACRO_REST(__VA_ARGS__));                  \
        }                                                                        \
    }                                                                            \
    G_STMT_END

#define _NMLOG2(level, call_id, ...)                                                             \
    G_STMT_START                                                                                 \
    {                                                                                            \
        NMSecretAgentCallId *const _call_id = (call_id);                                         \
                                                                                                 \
        nm_assert(_call_id);                                                                     \
                                                                                                 \
        nm_log((level),                                                                          \
               (_NMLOG_DOMAIN),                                                                  \
               NULL,                                                                             \
               NULL,                                                                             \
               "%s[" NM_HASH_OBFUSCATE_PTR_FMT "] request [" NM_HASH_OBFUSCATE_PTR_FMT           \
               ",%s,%s%s%s%s]: " _NM_UTILS_MACRO_FIRST(__VA_ARGS__),                             \
               _NMLOG_PREFIX_NAME,                                                               \
               NM_HASH_OBFUSCATE_PTR(_call_id->self),                                            \
               NM_HASH_OBFUSCATE_PTR(_call_id),                                                  \
               _call_id->method_name,                                                            \
               NM_PRINT_FMT_QUOTE_STRING(_call_id->path),                                        \
               (_call_id->cancellable ? "" : " (cancelled)") _NM_UTILS_MACRO_REST(__VA_ARGS__)); \
    }                                                                                            \
    G_STMT_END

/*****************************************************************************/

static NM_UTILS_FLAGS2STR_DEFINE(_capabilities_to_string,
                                 NMSecretAgentCapabilities,
                                 NM_UTILS_FLAGS2STR(NM_SECRET_AGENT_CAPABILITY_NONE, "none"),
                                 NM_UTILS_FLAGS2STR(NM_SECRET_AGENT_CAPABILITY_VPN_HINTS,
                                                    "vpn-hints"), );

/*****************************************************************************/

struct _NMSecretAgentCallId {
    CList                 lst;
    NMSecretAgent        *self;
    GCancellable         *cancellable;
    char                 *path;
    const char           *method_name;
    char                 *setting_name;
    NMSecretAgentCallback callback;
    gpointer              callback_data;
};

static NMSecretAgentCallId *
_call_id_new(NMSecretAgent        *self,
             const char           *method_name, /* this must be a static string. */
             const char           *path,
             const char           *setting_name,
             NMSecretAgentCallback callback,
             gpointer              callback_data)
{
    NMSecretAgentPrivate *priv = NM_SECRET_AGENT_GET_PRIVATE(self);
    NMSecretAgentCallId  *call_id;

    call_id  = g_slice_new(NMSecretAgentCallId);
    *call_id = (NMSecretAgentCallId){
        .self          = g_object_ref(self),
        .path          = g_strdup(path),
        .setting_name  = g_strdup(setting_name),
        .method_name   = method_name,
        .callback      = callback,
        .callback_data = callback_data,
        .cancellable   = g_cancellable_new(),
    };
    c_list_link_tail(&priv->requests, &call_id->lst);

    _LOG2T(call_id, "new request...");

    if (!priv->shutdown_wait_obj_registered) {
        /* self has async requests (that keep self alive). As long as
         * we have pending requests, shutdown is blocked. */
        priv->shutdown_wait_obj_registered = TRUE;
        nm_shutdown_wait_obj_register_object(G_OBJECT(self), "secret-agent");
    }

    return call_id;
}

#define _call_id_new(self, method_name, path, setting_name, callback, callback_data) \
    _call_id_new(self, "" method_name "", path, setting_name, callback, callback_data)

static void
_call_id_free(NMSecretAgentCallId *call_id)
{
    c_list_unlink_stale(&call_id->lst);
    g_free(call_id->path);
    g_free(call_id->setting_name);
    nm_g_object_unref(call_id->cancellable);
    g_object_unref(call_id->self);
    nm_g_slice_free(call_id);
}

static void
_call_id_invoke_callback(NMSecretAgentCallId *call_id,
                         GVariant            *secrets,
                         GError              *error,
                         gboolean             cancelled,
                         gboolean             free_call_id)
{
    gs_free_error GError *error_cancelled = NULL;

    nm_assert(call_id);
    nm_assert(!c_list_is_empty(&call_id->lst));

    c_list_unlink(&call_id->lst);

    if (cancelled) {
        nm_assert(!secrets);
        nm_assert(!error);
        if (call_id->callback) {
            nm_utils_error_set_cancelled(&error_cancelled, FALSE, "NMSecretAgent");
            error = error_cancelled;
        }
        _LOG2T(call_id, "cancelled");
    } else if (error) {
        nm_assert(!secrets);
        _LOG2T(call_id, "completed with failure: %s", error->message);
    } else {
        nm_assert(!secrets || g_variant_is_of_type(secrets, G_VARIANT_TYPE("a{sa{sv}}")));
        nm_assert((!!secrets) == nm_streq0(call_id->method_name, METHOD_GET_SECRETS));
        _LOG2T(call_id, "completed successfully");
    }

    if (call_id->callback)
        call_id->callback(call_id->self, call_id, secrets, error, call_id->callback_data);

    if (free_call_id)
        _call_id_free(call_id);
}

/*****************************************************************************/

static char *
_create_description(const char *dbus_owner, const char *identifier, gulong uid)
{
    return g_strdup_printf("%s/%s/%lu", dbus_owner, identifier, uid);
}

const char *
nm_secret_agent_get_description(NMSecretAgent *agent)
{
    NMSecretAgentPrivate *priv;

    g_return_val_if_fail(NM_IS_SECRET_AGENT(agent), NULL);

    priv = NM_SECRET_AGENT_GET_PRIVATE(agent);
    if (!priv->description) {
        priv->description =
            _create_description(priv->dbus_owner,
                                priv->identifier,
                                nm_auth_subject_get_unix_process_uid(priv->subject));
    }

    return priv->description;
}

/*****************************************************************************/

const char *
nm_secret_agent_get_dbus_owner(NMSecretAgent *agent)
{
    g_return_val_if_fail(NM_IS_SECRET_AGENT(agent), NULL);

    return NM_SECRET_AGENT_GET_PRIVATE(agent)->dbus_owner;
}

const char *
nm_secret_agent_get_identifier(NMSecretAgent *agent)
{
    g_return_val_if_fail(NM_IS_SECRET_AGENT(agent), NULL);

    return NM_SECRET_AGENT_GET_PRIVATE(agent)->identifier;
}

gulong
nm_secret_agent_get_owner_uid(NMSecretAgent *agent)
{
    g_return_val_if_fail(NM_IS_SECRET_AGENT(agent), G_MAXULONG);

    return nm_auth_subject_get_unix_process_uid(NM_SECRET_AGENT_GET_PRIVATE(agent)->subject);
}

const char *
nm_secret_agent_get_owner_username(NMSecretAgent *agent)
{
    g_return_val_if_fail(NM_IS_SECRET_AGENT(agent), NULL);

    return NM_SECRET_AGENT_GET_PRIVATE(agent)->owner_username;
}

gulong
nm_secret_agent_get_pid(NMSecretAgent *agent)
{
    g_return_val_if_fail(NM_IS_SECRET_AGENT(agent), G_MAXULONG);

    return nm_auth_subject_get_unix_process_pid(NM_SECRET_AGENT_GET_PRIVATE(agent)->subject);
}

NMSecretAgentCapabilities
nm_secret_agent_get_capabilities(NMSecretAgent *agent)
{
    g_return_val_if_fail(NM_IS_SECRET_AGENT(agent), NM_SECRET_AGENT_CAPABILITY_NONE);

    return NM_SECRET_AGENT_GET_PRIVATE(agent)->capabilities;
}

NMAuthSubject *
nm_secret_agent_get_subject(NMSecretAgent *agent)
{
    g_return_val_if_fail(NM_IS_SECRET_AGENT(agent), NULL);

    return NM_SECRET_AGENT_GET_PRIVATE(agent)->subject;
}

/*****************************************************************************/

/**
 * nm_secret_agent_add_permission:
 * @agent: A #NMSecretAgent.
 * @permission: The name of the permission
 *
 * Records whether or not the agent has a given permission.
 */
void
nm_secret_agent_add_permission(NMSecretAgent *agent, const char *permission, gboolean allowed)
{
    NMSecretAgentPrivate *priv;
    NMCListElem          *elem;

    g_return_if_fail(agent != NULL);
    g_return_if_fail(permission != NULL);

    priv = NM_SECRET_AGENT_GET_PRIVATE(agent);

    elem = nm_c_list_elem_find_first(&priv->permissions, p, nm_streq(p, permission));

    if (elem) {
        if (!allowed)
            nm_c_list_elem_free_full(elem, g_free);
        return;
    }

    if (allowed) {
        c_list_link_tail(&priv->permissions, &nm_c_list_elem_new_stale(g_strdup(permission))->lst);
    }
}

/**
 * nm_secret_agent_has_permission:
 * @agent: A #NMSecretAgent.
 * @permission: The name of the permission to check for
 *
 * Returns whether or not the agent has the given permission.
 *
 * Returns: %TRUE if the agent has the given permission, %FALSE if it does not
 * or if the permission was not previous recorded with
 * nm_secret_agent_add_permission().
 */
gboolean
nm_secret_agent_has_permission(NMSecretAgent *agent, const char *permission)
{
    g_return_val_if_fail(agent != NULL, FALSE);
    g_return_val_if_fail(permission != NULL, FALSE);

    return !!nm_c_list_elem_find_first(&NM_SECRET_AGENT_GET_PRIVATE(agent)->permissions,
                                       p,
                                       nm_streq(p, permission));
}

/*****************************************************************************/

static void
_dbus_call_cb(GObject *source, GAsyncResult *result, gpointer user_data)
{
    NMSecretAgentCallId       *call_id;
    gs_unref_variant GVariant *ret     = NULL;
    gs_unref_variant GVariant *secrets = NULL;
    gs_free_error GError      *error   = NULL;

    ret = g_dbus_connection_call_finish(G_DBUS_CONNECTION(source), result, &error);

    if (!ret && nm_utils_error_is_cancelled(error))
        return;

    call_id = user_data;

    if (!ret)
        g_dbus_error_strip_remote_error(error);
    else {
        if (nm_streq(call_id->method_name, METHOD_GET_SECRETS)) {
            g_variant_get(ret, "(@a{sa{sv}})", &secrets);
        }
    }

    _call_id_invoke_callback(call_id, secrets, error, FALSE, TRUE);
}

/*****************************************************************************/

NMSecretAgentCallId *
nm_secret_agent_get_secrets(NMSecretAgent               *self,
                            const char                  *path,
                            NMConnection                *connection,
                            const char                  *setting_name,
                            const char                 **hints,
                            NMSecretAgentGetSecretsFlags flags,
                            NMSecretAgentCallback        callback,
                            gpointer                     callback_data)
{
    NMSecretAgentPrivate *priv;
    GVariant             *dict;
    NMSecretAgentCallId  *call_id;

    g_return_val_if_fail(NM_IS_SECRET_AGENT(self), NULL);
    g_return_val_if_fail(NM_IS_CONNECTION(connection), NULL);
    g_return_val_if_fail(path && *path, NULL);
    g_return_val_if_fail(setting_name, NULL);
    g_return_val_if_fail(callback, NULL);

    priv = NM_SECRET_AGENT_GET_PRIVATE(self);

    dict = nm_connection_to_dbus(connection, NM_CONNECTION_SERIALIZE_ALL);

    /* Mask off the private flags if present */
    flags &= ~(NM_SECRET_AGENT_GET_SECRETS_FLAG_ONLY_SYSTEM
               | NM_SECRET_AGENT_GET_SECRETS_FLAG_NO_ERRORS);

    call_id = _call_id_new(self, METHOD_GET_SECRETS, path, setting_name, callback, callback_data);

    g_dbus_connection_call(priv->dbus_connection,
                           priv->dbus_owner,
                           NM_DBUS_PATH_SECRET_AGENT,
                           NM_DBUS_INTERFACE_SECRET_AGENT,
                           call_id->method_name,
                           g_variant_new("(@a{sa{sv}}os^asu)",
                                         dict,
                                         path,
                                         setting_name,
                                         hints ?: NM_PTRARRAY_EMPTY(const char *),
                                         (guint32) flags),
                           G_VARIANT_TYPE("(a{sa{sv}})"),
                           G_DBUS_CALL_FLAGS_NO_AUTO_START,
                           120000,
                           call_id->cancellable,
                           _dbus_call_cb,
                           call_id);

    return call_id;
}

/*****************************************************************************/

static void
_call_cancel_cb(GObject *source, GAsyncResult *result, gpointer user_data)
{
    NMSecretAgentCallId       *call_id = user_data;
    gs_free_error GError      *error   = NULL;
    gs_unref_variant GVariant *ret     = NULL;

    ret = g_dbus_connection_call_finish(G_DBUS_CONNECTION(source), result, &error);

    if (ret)
        _LOG2T(call_id, "success cancelling GetSecrets");
    else if (g_error_matches(error, G_DBUS_ERROR, G_DBUS_ERROR_SERVICE_UNKNOWN))
        _LOG2T(call_id, "cancelling GetSecrets no longer works as service disconnected");
    else {
        _LOG2T(call_id, "failed to cancel GetSecrets: %s", error->message);
    }

    _call_id_free(call_id);
}

/**
 * nm_secret_agent_cancel_call:
 * @self: the #NMSecretAgent instance for the @call_id.
 *   Maybe be %NULL if @call_id is %NULL.
 * @call_id: (allow-none): the call id to cancel. May be %NULL for convenience,
 *   in which case it does nothing.
 *
 * It is an error to pass an invalid @call_id or a @call_id for an operation
 * that already completed. It is also an error to cancel the call from inside
 * the callback, at that point the call is already completed.
 * In case of nm_secret_agent_cancel_call() this will synchronously invoke the
 * callback before nm_secret_agent_cancel_call() returns.
 */
void
nm_secret_agent_cancel_call(NMSecretAgent *self, NMSecretAgentCallId *call_id)
{
    NMSecretAgentPrivate *priv;
    gboolean              free_call_id = TRUE;

    if (!call_id) {
        /* for convenience, %NULL is accepted fine. */
        nm_assert(!self || NM_IS_SECRET_AGENT(self));
        return;
    }

    g_return_if_fail(NM_IS_SECRET_AGENT(call_id->self));
    g_return_if_fail(!c_list_is_empty(&call_id->lst));

    /* Theoretically, call-id already has a self pointer. But nm_secret_agent_cancel_call() has only
     * one user: NMAgentManager. And that one has the self-pointer at hand, so the only purpose of
     * the @self argument is to assert that we are cancelling the expected call.
     *
     * We could drop the @self argument, but that just remove an additional assert-check from
     * our code, without making a simplification for the only caller of this function. */
    g_return_if_fail(self == call_id->self);

    priv = NM_SECRET_AGENT_GET_PRIVATE(self);

    nm_assert(c_list_contains(&priv->requests, &call_id->lst));

    nm_clear_g_cancellable(&call_id->cancellable);

    if (nm_streq(call_id->method_name, METHOD_GET_SECRETS)) {
        g_dbus_connection_call(
            priv->dbus_connection,
            priv->dbus_owner,
            NM_DBUS_PATH_SECRET_AGENT,
            NM_DBUS_INTERFACE_SECRET_AGENT,
            METHOD_CANCEL_GET_SECRETS,
            g_variant_new("(os)", call_id->path, call_id->setting_name),
            G_VARIANT_TYPE("()"),
            G_DBUS_CALL_FLAGS_NO_AUTO_START,
            NM_SHUTDOWN_TIMEOUT_1500_MSEC,
            NULL, /* this operation is not cancellable. We rely on the timeout. */
            _call_cancel_cb,
            call_id);
        /* we keep call-id alive, but it will be unlinked from priv->requests.
         * _call_cancel_cb() will finally free it later. */
        free_call_id = FALSE;
    }

    _call_id_invoke_callback(call_id, NULL, NULL, TRUE, free_call_id);
}

/*****************************************************************************/

NMSecretAgentCallId *
nm_secret_agent_save_secrets(NMSecretAgent        *self,
                             const char           *path,
                             NMConnection         *connection,
                             NMSecretAgentCallback callback,
                             gpointer              callback_data)
{
    NMSecretAgentPrivate *priv;
    GVariant             *dict;
    NMSecretAgentCallId  *call_id;

    g_return_val_if_fail(NM_IS_SECRET_AGENT(self), NULL);
    g_return_val_if_fail(NM_IS_CONNECTION(connection), NULL);
    g_return_val_if_fail(path && *path, NULL);

    priv = NM_SECRET_AGENT_GET_PRIVATE(self);

    /* Caller should have ensured that only agent-owned secrets exist in 'connection' */
    dict = nm_connection_to_dbus(connection, NM_CONNECTION_SERIALIZE_ALL);

    call_id = _call_id_new(self, METHOD_SAVE_SECRETS, path, NULL, callback, callback_data);

    g_dbus_connection_call(priv->dbus_connection,
                           priv->dbus_owner,
                           NM_DBUS_PATH_SECRET_AGENT,
                           NM_DBUS_INTERFACE_SECRET_AGENT,
                           call_id->method_name,
                           g_variant_new("(@a{sa{sv}}o)", dict, path),
                           G_VARIANT_TYPE("()"),
                           G_DBUS_CALL_FLAGS_NO_AUTO_START,
                           60000,
                           call_id->cancellable,
                           _dbus_call_cb,
                           call_id);

    return call_id;
}

/*****************************************************************************/

NMSecretAgentCallId *
nm_secret_agent_delete_secrets(NMSecretAgent        *self,
                               const char           *path,
                               NMConnection         *connection,
                               NMSecretAgentCallback callback,
                               gpointer              callback_data)
{
    NMSecretAgentPrivate *priv;
    GVariant             *dict;
    NMSecretAgentCallId  *call_id;

    g_return_val_if_fail(NM_IS_SECRET_AGENT(self), NULL);
    g_return_val_if_fail(NM_IS_CONNECTION(connection), NULL);
    g_return_val_if_fail(path && *path, NULL);

    priv = NM_SECRET_AGENT_GET_PRIVATE(self);

    /* No secrets sent; agents must be smart enough to track secrets using the UUID or something */
    dict = nm_connection_to_dbus(connection, NM_CONNECTION_SERIALIZE_WITH_NON_SECRET);

    call_id = _call_id_new(self, METHOD_DELETE_SECRETS, path, NULL, callback, callback_data);

    g_dbus_connection_call(priv->dbus_connection,
                           priv->dbus_owner,
                           NM_DBUS_PATH_SECRET_AGENT,
                           NM_DBUS_INTERFACE_SECRET_AGENT,
                           call_id->method_name,
                           g_variant_new("(@a{sa{sv}}o)", dict, path),
                           G_VARIANT_TYPE("()"),
                           G_DBUS_CALL_FLAGS_NO_AUTO_START,
                           60000,
                           call_id->cancellable,
                           _dbus_call_cb,
                           call_id);
    return call_id;
}

/*****************************************************************************/

static void
name_owner_changed(NMSecretAgent *self, const char *owner)
{
    NMSecretAgentPrivate *priv = NM_SECRET_AGENT_GET_PRIVATE(self);

    nm_assert(!priv->name_owner_cancellable);

    owner = nm_str_not_empty(owner);

    _LOGT("name-owner-changed: %s%s%s",
          NM_PRINT_FMT_QUOTED(owner, "has ", owner, "", "disconnected"));

    if (owner)
        return;

    nm_clear_g_dbus_connection_signal(priv->dbus_connection, &priv->name_owner_changed_id);

    g_signal_emit(self, signals[DISCONNECTED], 0);
}

static void
name_owner_changed_cb(GDBusConnection *dbus_connection,
                      const char      *sender_name,
                      const char      *object_path,
                      const char      *interface_name,
                      const char      *signal_name,
                      GVariant        *parameters,
                      gpointer         user_data)
{
    NMSecretAgent *self      = NM_SECRET_AGENT(user_data);
    const char    *new_owner = NULL;

    if (g_variant_is_of_type(parameters, G_VARIANT_TYPE("(sss)"))) {
        g_variant_get(parameters, "(&s&s&s)", NULL, NULL, &new_owner);
    }

    nm_clear_g_cancellable(&NM_SECRET_AGENT_GET_PRIVATE(self)->name_owner_cancellable);

    name_owner_changed(self, new_owner);
}

static void
get_name_owner_cb(const char *name_owner, GError *error, gpointer user_data)
{
    NMSecretAgent *self;

    if (!name_owner && g_error_matches(error, G_IO_ERROR, G_IO_ERROR_CANCELLED))
        return;

    self = user_data;

    g_clear_object(&NM_SECRET_AGENT_GET_PRIVATE(self)->name_owner_cancellable);

    name_owner_changed(self, name_owner);
}

/*****************************************************************************/

NMSecretAgent *
nm_secret_agent_new(GDBusMethodInvocation    *context,
                    NMAuthSubject            *subject,
                    const char               *identifier,
                    NMSecretAgentCapabilities capabilities)
{
    NMSecretAgent        *self;
    NMSecretAgentPrivate *priv;
    const char           *dbus_owner;
    gs_free char         *owner_username = NULL;
    char                 *description    = NULL;
    char                  buf_subject[64];
    char                  buf_caps[150];
    gulong                uid;
    GDBusConnection      *dbus_connection;

    g_return_val_if_fail(context != NULL, NULL);
    g_return_val_if_fail(NM_IS_AUTH_SUBJECT(subject), NULL);
    g_return_val_if_fail(nm_auth_subject_get_subject_type(subject)
                             == NM_AUTH_SUBJECT_TYPE_UNIX_PROCESS,
                         NULL);
    g_return_val_if_fail(identifier != NULL, NULL);

    dbus_connection = g_dbus_method_invocation_get_connection(context);

    g_return_val_if_fail(G_IS_DBUS_CONNECTION(dbus_connection), NULL);

    uid = nm_auth_subject_get_unix_process_uid(subject);

    owner_username = nm_utils_uid_to_name(uid);

    dbus_owner = nm_auth_subject_get_unix_process_dbus_sender(subject);

    self = g_object_new(NM_TYPE_SECRET_AGENT, NULL);

    priv = NM_SECRET_AGENT_GET_PRIVATE(self);

    priv->dbus_connection = g_object_ref(dbus_connection);

    _LOGT("constructed: %s, owner=%s%s%s (%s), unique-name=%s%s%s, capabilities=%s",
          (description = _create_description(dbus_owner, identifier, uid)),
          NM_PRINT_FMT_QUOTE_STRING(owner_username),
          nm_auth_subject_to_string(subject, buf_subject, sizeof(buf_subject)),
          NM_PRINT_FMT_QUOTE_STRING(g_dbus_connection_get_unique_name(priv->dbus_connection)),
          _capabilities_to_string(capabilities, buf_caps, sizeof(buf_caps)));

    priv->identifier     = g_strdup(identifier);
    priv->owner_username = g_steal_pointer(&owner_username);
    priv->dbus_owner     = g_strdup(dbus_owner);
    priv->description    = description;
    priv->capabilities   = capabilities;
    priv->subject        = g_object_ref(subject);

    priv->name_owner_changed_id =
        nm_dbus_connection_signal_subscribe_name_owner_changed(priv->dbus_connection,
                                                               priv->dbus_owner,
                                                               name_owner_changed_cb,
                                                               self,
                                                               NULL);

    priv->name_owner_cancellable = g_cancellable_new();
    nm_dbus_connection_call_get_name_owner(priv->dbus_connection,
                                           priv->dbus_owner,
                                           -1,
                                           priv->name_owner_cancellable,
                                           get_name_owner_cb,
                                           self);

    return self;
}

static void
nm_secret_agent_init(NMSecretAgent *self)
{
    NMSecretAgentPrivate *priv;

    priv = G_TYPE_INSTANCE_GET_PRIVATE(self, NM_TYPE_SECRET_AGENT, NMSecretAgentPrivate);

    self->_priv = priv;

    c_list_init(&self->agent_lst);
    c_list_init(&priv->permissions);
    c_list_init(&priv->requests);
}

static void
dispose(GObject *object)
{
    NMSecretAgent        *self = NM_SECRET_AGENT(object);
    NMSecretAgentPrivate *priv = NM_SECRET_AGENT_GET_PRIVATE(self);

    nm_assert(c_list_is_empty(&self->agent_lst));
    nm_assert(!self->auth_chain);
    nm_assert(c_list_is_empty(&priv->requests));

    nm_clear_g_dbus_connection_signal(priv->dbus_connection, &priv->name_owner_changed_id);

    nm_clear_g_cancellable(&priv->name_owner_cancellable);

    G_OBJECT_CLASS(nm_secret_agent_parent_class)->dispose(object);
}

static void
finalize(GObject *object)
{
    NMSecretAgent        *self = NM_SECRET_AGENT(object);
    NMSecretAgentPrivate *priv = NM_SECRET_AGENT_GET_PRIVATE(self);

    g_free(priv->description);
    g_free(priv->identifier);
    g_free(priv->owner_username);
    g_free(priv->dbus_owner);

    nm_c_list_elem_free_all(&priv->permissions, g_free);

    g_clear_object(&priv->subject);

    g_clear_object(&priv->dbus_connection);

    G_OBJECT_CLASS(nm_secret_agent_parent_class)->finalize(object);

    _LOGT("finalized");
}

static void
nm_secret_agent_class_init(NMSecretAgentClass *config_class)
{
    GObjectClass *object_class = G_OBJECT_CLASS(config_class);

    g_type_class_add_private(object_class, sizeof(NMSecretAgentPrivate));

    object_class->dispose  = dispose;
    object_class->finalize = finalize;

    signals[DISCONNECTED] = g_signal_new(NM_SECRET_AGENT_DISCONNECTED,
                                         G_OBJECT_CLASS_TYPE(object_class),
                                         G_SIGNAL_RUN_FIRST,
                                         0,
                                         NULL,
                                         NULL,
                                         g_cclosure_marshal_VOID__VOID,
                                         G_TYPE_NONE,
                                         0);
}